5класс .Уравнение. 252:у=21

<span>3a+8a=1, 87</span>

(2 3/8 : 3/4 - 24 7/9) : (7 1/8 - 157 4/5 : 24)

1) 2 3/8 : 3/4 = 19/8 * 4/3 = 19/6 = 3 1/6,

2) 3 1/6 - 24 7/9 = 19/6 - 223/9 = 57/18 - 446/18 = -389/18 = -21  11/18,

3) 157 4/5 : 24 = 789/5 * 1/24 = 263/40 = 6 3/40,

4) 7 1/8 - 6 3/40 = 57/8 - 263/40 = 285/40 - 263/40 = 22/40 = 11/20,

5) -21 11/18 : 11/20 = -389/18 * 20/11 = -3890/99 = -39 29/99